Database language Structured Query Language (SQL) is a language used to enter and retrieve information from a SQL database. SQL can be embedded in application source code, but it is not a programming language. To write a program that accesses a database, a developer starts with a conventional programming language, such as COBOL, PL/I, FORTRAN, C, or Pascal and embeds SQL statements directly into the program's source code, intermixed with the other programming language statements. Certain SQL statements are used to retrieve data into the program. A SQL pre-compiler accepts the combined source code and separates the SQL statements from the conventional programming language statements.
Executable modules for application programs may be run in separate environments on a single system. For example, quality assurance, performance test, parallel test, and multiple versions of an application executable may be required by different developers on a single system. SQL modules are stored in a fixed location, thus complicating development and deployment issues when multiple environments are present.
Developers compile application code once for post development environments. After an application program has been released, tested, and accepted there is no provision to allow the source code to be pre-processed or language compiled. To pre-process or language compile a program subsequent to acceptance would be contrary to standard release practices.